I would NOT recommend using glue remover or a heat gun. Simply pull an edge up slowly then gently start to peel it off.
I took mine off last weekend with nothing more than a Zip Tie used to get under the edge to pull it up where I could get hold of it. It litterally took me about 1m to do all the doors.
I then claybared to get any specs off and waxed it. Easy. The glue remover and / or heat gun will cause the tape to come off on the car MORE rather than less. I had only a couple real tiny places where the glue stuck and I simply just rolled it off with my finger.
FYI - It was about 50 to 60deg outside when I did mine.
Anyone have any pics of a Speed3 without the door trims on it, also how easy are they to get off and did you notice a color difference after they were removed?